Tail-end distributed variable-frequency energy-saving waste heat supply system

Abstract

The utility model discloses a tail end distributed frequency conversion energy-saving waste heat heating system which comprises a smoke exhaust system connected to a boiler through a smoke pipeline, a heat pump unit and a PLC (Programmable Logic Controller), and an induced draft fan is arranged on the smoke pipeline; a first heat exchanger and a second heat exchanger are sequentially arranged on a smoke pipeline behind the boiler, the water inlet end of the first heat exchanger is connected with a heat supply network water return pipe, the water inlet end of the second heat exchanger is connected with a cooling water source, and the water outlet ends of the first heat exchanger and the second heat exchanger are connected with the two water inlet ends of the heat pump unit respectively. A first pump machine is arranged on a pipeline connecting the first heat exchanger and the heat pump unit, and a second pump machine is arranged on a pipeline connecting the second heat exchanger and the heat pump unit. Heat supply network return water and a cooling water source are heated through the two stages of heat exchangers respectively, waste heat in smoke is recycled, water obtained after heat exchange enters the heat pump unit for heating, the heat supply cost is reduced, and the heat supply efficiency of a heat supply network can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of heating units, and more specifically to a terminal distributed variable frequency energy-saving waste heat heating system. Background Art

[0002] In northern my country, the heating form of winter is mostly centralized heating. The heating company heats the water and transmits it to the heat-using units through the pipeline network. The heat network return water of the heat-using units is returned to the heating company for heating and then transmitted to the heat-using units.

[0003] At present, most heating companies adopt the form of boiler combustion, using the heat of boiler combustion as the heat source of the heat pump unit through the steam turbine to heat the return water of the heating network to supply heat to the heat-using units.

[0004] The boiler will generate a lot of flue gas during the combustion process. The heating company needs to purify the flue gas before it is discharged to meet environmental protection requirements. Since the temperature of the flue gas discharged by the boiler is relatively high, it cannot fully utilize the heat in the flue gas if it is directly discharged after treatment, resulting in a certain amount of heat loss. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a terminal distributed variable frequency energy-saving waste heat heating system to reuse the waste heat in the flue gas and reduce the heating cost.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows.

[0007] The terminal distributed variable frequency energy-saving waste heat heating system includes a smoke exhaust system connected to the boiler through a smoke pipe for treating the smoke, a heat pump unit connected to the boiler through a steam turbine for heating the water in the heat network, and a PLC controller for controlling heating and heat supply. The smoke pipe is provided with an induced draft fan for introducing the smoke in the boiler into the smoke exhaust system; the smoke pipe behind the boiler is provided with a first heat exchanger and a second heat exchanger in sequence, the water inlet end of the first heat exchanger is connected to the return water pipe of the heat network, the water inlet end of the second heat exchanger is connected to the cooling water source, and the water outlet ends of the first heat exchanger and the second heat exchanger are respectively connected to the two water inlet ends of the heat pump unit. A first pump is arranged on the pipeline connecting the first heat exchanger and the heat pump unit, and a second pump is arranged on the pipeline connecting the second heat exchanger and the heat pump unit; the water outlet of the heat pump unit is connected to the water supply pipe of the heating network through a peak heater; the water supply pipe of the heating network is provided with a fourth temperature sensor for collecting the heating temperature of the heating network, and the water outlet pipe of the heat pump unit is provided with a third temperature sensor for collecting the water outlet temperature of the heat pump unit, the output ends of the third temperature sensor and the fourth temperature sensor are respectively connected to the input end of the PLC controller, and the output end of the PLC controller is respectively connected to the input ends of the first pump, the second pump body and the peak heater.

[0008] To further optimize the technical solution, a first temperature sensor and a first control valve are provided on the pipeline connecting the first heat exchanger and the heat pump unit, the output end of the first temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is connected to the input end of the first control valve.

[0009] To further optimize the technical solution, a second temperature sensor and a second control valve are provided on the pipeline connecting the second heat exchanger and the heat pump unit, the output end of the second temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is connected to the input end of the second control valve.

[0010] To further optimize the technical solution, a bypass pipeline is connected in parallel to the peak heater, and a fourth control valve for controlling whether to connect to the bypass pipeline is provided on the bypass pipeline. A third control valve for controlling whether peak heating is performed is provided at the front end of the peak heater, and the input ends of the third control valve and the fourth control valve are respectively connected to the output end of the PLC controller.

[0011] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0012] The terminal distributed variable frequency energy-saving waste heat heating system provided by the utility model heats the return water of the heating network and the cooling water source respectively through a two-stage heat exchanger, reuses the waste heat in the flue gas, and the water after heat exchange enters the heat pump unit for heating, which not only reduces the heating cost, but also improves the heating efficiency of the heating network. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the utility model.

[0014] Among them: 1. Boiler, 2. Flue gas duct, 3. First heat exchanger, 4. Heat network return pipe, 5. Cooling water source, 6. Second heat exchanger, 7. Induced draft fan, 8. Smoke exhaust system, 9. Steam turbine, 10. First pump, 11. First control valve, 12. First temperature sensor, 13. Second pump, 14. Second control valve, 15. Second temperature sensor, 16. Heat pump unit, 17. Third temperature sensor, 18. Peak heater, 19. Third control valve, 20. Fourth control valve, 21. Heat network water supply pipe, 22. Fourth temperature sensor. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Terminal distributed variable frequency energy-saving waste heat heating system, combined with Figure 1As shown, it includes a boiler 1, a smoke exhaust system 8, a heat pump unit 16 and a PLC controller. The smoke exhaust system 8 is connected to the boiler 1 through a smoke duct 2 to process the smoke exhausted by the boiler. The smoke duct 2 is provided with an induced draft fan 7 to introduce the smoke in the boiler into the smoke exhaust system for smoke treatment. The heat pump unit 16 is connected to the boiler 1 through a steam turbine 9 to heat the water in the heating network and provide a heat source for the heat user. The PLC controller is used to control heating and heat supply.

[0017] A first heat exchanger 3 and a second heat exchanger 6 are sequentially arranged on the flue gas duct 2 behind the boiler 1. The water inlet end of the first heat exchanger 3 is connected to the heat network return pipe 4 for heat exchange and heating of the heat network return water. The water inlet end of the second heat exchanger is connected to the cooling water source 5 for secondary heat exchange between the cooling water and the exhausted flue gas, which not only reduces the flue gas temperature but also heats the cooling water. The water outlet ends of the first heat exchanger 3 and the second heat exchanger 6 are respectively connected to the two water inlet ends of the heat pump unit 16. The heat network return water enters the heat pump unit for heating after primary heating by the first heat exchanger. The cooling water source for replenishing the heat pump unit enters the heat pump unit after secondary heating by the second heat exchanger. After heat exchange through the two-stage heat exchanger, the water inlet temperature of the heat pump unit is increased, thereby reducing the energy consumption of the heat pump unit.

[0018] A first pump 10, a first temperature sensor 12 and a first control valve 11 are provided on the pipeline connecting the first heat exchanger 3 and the heat pump unit 16. The first pump 10 is used to send the return water of the hot network after heat exchange of the first heat exchanger into the heat pump unit for heating. The first temperature sensor is used to collect the temperature of the return water of the hot network after heat exchange. The first control valve is used to control the amount of return water of the hot network entering the heat pump unit after heat exchange. The output end of the first temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is respectively connected to the input ends of the first pump and the first control valve.

[0019] A second pump 13, a second temperature sensor 15 and a second control valve 14 are provided on the pipeline connecting the second heat exchanger 6 and the heat pump unit 16. The second pump is used to send the cooling water source heat exchanged by the second heat exchanger into the heat pump unit for heating. The second temperature sensor is used to collect the temperature of the cooling water source after heat exchange. The second control valve is used to control the amount of cooling water source entering the heat pump unit after heat exchange. The output end of the second temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is respectively connected to the input end of the second pump and the input end of the second control valve.

[0020] When the first temperature sensor 12 detects that the temperature of the heat network return water heat exchange is high, the temperature difference between it and the temperature set by the heat pump unit is small. At this time, energy saving and consumption reduction are achieved by reducing the work of the steam turbine. When the heat pump unit needs to be replenished with water, the work of the steam turbine is adjusted according to the replenishment temperature collected by the second temperature sensor to achieve rapid heating of the heat network water.

[0021] The water outlet of the heat pump unit 16 is connected to the heat network water supply pipe 21 through the peak heater 18. The heat network water supply pipe 21 is provided with a fourth sensor 22 for collecting the heating temperature of the heat network. The water outlet pipe of the heat pump unit 16 is provided with a third temperature sensor 17 for collecting the outlet water temperature of the heat pump unit. The output ends of the third temperature sensor and the fourth temperature sensor are respectively connected to the input ends of the PLC controller, and the output end of the PLC controller is connected to the input end of the peak heater. When the heat network temperature detected by the fourth temperature sensor cannot reach the set heat network heating temperature, the peak heater performs peak heating on the outlet water of the heat pump unit to reach the set temperature of the heat network water supply.

[0022] When the temperature detected by the third sensor reaches the set temperature of the heating network, the peak heater 18 is not used when supplying water to the heating network. A bypass pipeline is connected in parallel at both ends of the peak heater 18. The outlet water of the heat pump unit is connected to the heating network water supply pipe 21 through the bypass pipeline. The front end of the peak heater is provided with a third control valve 19, and the bypass pipeline is provided with a fourth control valve 20. The third control valve and the fourth control valve are used to realize whether the heating network water is subjected to peak heating. The input ends of the third control valve and the fourth control valve are respectively connected to the output end of the PLC controller. When peak heating is required, the fourth control valve 20 is closed and the third control valve 19 is opened. When peak heating is not required, the fourth control valve is opened and the third control valve is closed.

Claims

1. A terminal distributed variable frequency energy-saving waste heat heating system, comprising a smoke exhaust system (8) connected to a boiler (1) via a smoke pipe (2) for treating smoke, a heat pump unit (16) connected to the boiler (1) via a steam turbine (9) for heating water in a heating network, and a PLC controller for controlling heating and heat supply, wherein an induced draft fan (7) for introducing smoke in the boiler into the smoke exhaust system (8) is provided on the smoke pipe (2); the characteristics are as follows: A first heat exchanger (3) and a second heat exchanger (6) are sequentially arranged on the flue gas duct (2) behind the boiler (1); a water inlet end of the first heat exchanger (3) is connected to a heat network return pipe (4); a water inlet end of the second heat exchanger is connected to a cooling water source (5); water outlet ends of the first heat exchanger (3) and the second heat exchanger (6) are respectively connected to two water inlet ends of a heat pump unit (16); a first pump (10) is arranged on the pipe connecting the first heat exchanger (3) and the heat pump unit (16); and a second pump (10) is arranged on the pipe connecting the second heat exchanger (6) and the heat pump unit (16). (13); the water outlet of the heat pump unit (16) is connected to the heat network water supply pipe (21) through the peak heater (18); the heat network water supply pipe (21) is provided with a fourth temperature sensor (22) for collecting the heating temperature of the heat network, and the water outlet pipe of the heat pump unit (16) is provided with a third temperature sensor (17) for collecting the water outlet temperature of the heat pump unit, the output ends of the third temperature sensor and the fourth temperature sensor are respectively connected to the input end of the PLC controller, and the output end of the PLC controller is respectively connected to the input end of the first pump, the second pump body and the peak heater.

2. The terminal distributed variable frequency energy-saving waste heat heating system according to claim 1 is characterized in that: A first temperature sensor (12) and a first control valve (11) are provided on the pipeline connecting the first heat exchanger (3) and the heat pump unit (16); the output end of the first temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is connected to the input end of the first control valve.

3. The terminal distributed variable frequency energy-saving waste heat heating system according to claim 1 is characterized in that: A second temperature sensor (15) and a second control valve (14) are provided on the pipeline connecting the second heat exchanger (6) and the heat pump unit (16); the output end of the second temperature sensor is connected to the input end of the PLC controller, and the output end of the PLC controller is connected to the input end of the second control valve.

4. The terminal distributed variable frequency energy-saving waste heat heating system according to claim 1 is characterized in that: A bypass pipeline is connected in parallel to the peak heater (18), and a fourth control valve (20) is arranged on the bypass pipeline for controlling whether to connect to the bypass pipeline. A third control valve (19) is arranged at the front end of the peak heater (18) for controlling whether to perform peak heating, and the input ends of the third control valve and the fourth control valve are respectively connected to the output end of the PLC controller.

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